Digester Covers

Digester Covers Overview:

WesTech anaerobic digester covers are ideal for new and retrofit installations. These custom covers are innovatively designed by WesTech engineers who have decades of experience meeting customer specifications for biogas and odor containment. Incorporating the most current structural standards, WesTech covers are economical and easy to install.

WesTech offers three major structural designs: Steel Truss, Radial Beam, and DuoSphere™. Our Steel Truss and Radial Beam structures can be configured to fixed or buoyant configurations. Our DuoSphere Membrane Digester Cover is the most versatile cover available. The tank mount design provides an innovative and cost-effective solution for new and replacement covers.

Structural Designs

Radial Beam Structure: Beam covers are a very economical choice for anaerobic digester covers, as they have no ceiling plates and 50% less field weld length than a truss cover.

Steel Truss Structure: Truss covers use welded steel plates on both the top and bottom of the trusses to form an attic space, that protects the structural members from corrosion and provides insulation for the sludge.

DuoSphere: The DuoSphere membrane digester cover is the most versatile cover available. The tank mount design provides an innovative and cost-effective solution for new and replacement covers.

Additional WesTech Options:

Geomembrane seal

Hinged ballast block platform design

Digester Cover Types

Fixed Covers: Innovative cover designs incorporate a water launder or more advanced seal materials that overcome liquid level variation limitations. A conventional annular seal design relies on sidesheets submerged in the sludge to achieve a pressure seal and prevent odors from escaping.

Buoyant Covers: Buoyant floating covers are in contact with the sludge, which reduces the exposed liquid surface area and prevents a large scum blanket.

Gasholder Covers: Gasholder covers can be constructed using radial beams, trusses, or engineered textiles as in the case of the DuoSphere dual membrane covers.

Slide Guides for Gasholder and Buoyant Covers

WesTech’s Ultra-High Molecular Weight (UHMW) polyethylene slide plates, used on three sides of the structural steel tube, prevent covers from tipping and binding as they move vertically within the tank. They resist wind, seismic, and unbalanced loads in both radial and tangential directions. The durable, low-friction UHMW surfaces remove the need for lubrication, enabling maintenance-free operation.